Drop forging die structure



Oct. 25, 1938. MEN-VOL? 2,134,386

DROP FORGING DIE STRUCTURE Filed Nov. 4-, 1935 Patented Oct. 25, 1938 UNITED. S A -gs ,134,3 6 DROP rename DIE STRUCTURE Martin Benjamin ,Wolf, st. Catharines, Ontar o, I;

Canada, assignor to Thompson Broducts, In; corporatedpleveland, Ohio, a corporationof Ohio Application'Noveinber 4, 1935, Serial No. 48,155

In Canada September-'10, '1935 i illain (01; 76-95)" This invention relates to the drop forging of die formed articles, as for example rock drill bits, and particularly to improved die structure by means of which the forging can be more-efficiently and economically accomplished.

The invention consists essentially in forming the die structure from a plurality of cooperative parts and forging the metal into the shaped recess and thereafter collapsing the die for removal of the finished article.

An important object of the invention is to form the female die structure of a plurality of sections or segments which are accurately machined to fit intimately together to form the die, with dowel and securing means for accurately holding the segments together during the forging operation so as to produce articles free from burrs and ragged edges and thereby eliminating excessive grinding and trimming which often causes articles, such as drill bits, to be of light weight and not capable of attaining and keeping efilcient drilling speed.

A further object is to provide a die structure of similar symmetrical sections or segments so that in case any segment becomes damaged it may be replaced without having to throw away the entire die structure.

The various features of my invention are incorporated in the structure disclosed on the drawing, in which drawing Figure l is a plan View of a die structure cornpcsed of four quarters or segments;

Figure 2 is a side elevation of the structure of Figure 1;

Figure 3 is a side elevation of two adjacent quarters of a four-quarter die, showing the interior arrangement;

Figure 4 is a plan View of one of halves of a two-part die;

Figure 5 is a side elevation of the die half showing the interior arrangement;

Figure 6 is a side elevation of a die or mold part for application in the bottom of the cavity of the die body for molding the end of an article such as a drill bit; and

Figure '7 is a plan view of the molding element of Figure 6.

The die structure is of circular horizontal cross section throughout and the structure shown in Figures 1, 2 and 3 comprises four quarters or segments It, the inner faces II of the segments being accurately machined so that the segments may intimately fit together. The segments are held in accurate alignment by guide or dowel pins I2 and are drawn together and fastened by bolts I3 whose ends are kept. Within the circumferential surface of the die structure by being within recesses I3. 'Eachquarteris drilled and tapped, as indicatedat' I4, forreceivingcentering pins for'adjusting the position of the female die structures in relation to the male die or forging plunger P2 The interior of the die structure is machined out to receive the male die or forging plunger and to provide the mold cavity for the article to be forged. As shown the die structure has the outer bore I5 through which' the openings I4, the bore I5 being larger than the v bore I6.

Extending downwardly through the die struc- Q ture from the molding bore I1 is the passage I8 for receiving the pin I9 extendingfrom the die or mold member 20 which rests in the bottom of the mold space I7 and which is shaped at its top and sides to determine the shape of the end of the article to be molded, in this case the drill bit B which bit is shown as comprising a substantially cylindrical body with side cutting teeth a, and inner cross teeth b.

The dowel pins I2 will hold the segments accurately aligned and the bolts I3 will secure these segments together and the structure can then be placed in a lathe or other suitable machine for machining off the outer surface of the structure and the inner bores I5, I6, and the circumferential surface of the mold cavity I'I. The lower end of the structure may be frusto-conical as shown and may be seated in a correspondingly formed pocket 0 provided in a supporting base d so that under impact of the maledie or plunger the segments will be prevented from separating radially. Where the die or mold member 20 cannot be dropped into the segments after assembly thereof, it'is inserted during assembly of these segments and will then be held accurately in centered position at the bottom of the mold cavity I! by its supporting pin I9. A steel ingot of predetermined shape and size is now placed in the cavity I1, and, after the male die has been accurately aligned in the bore I5 and the upper end of the bore I6 by means of the centering pins engaging in the passages I4, the forging blows from burrs and ragged edges and will be ready for use.

In the modified arrangement illustrated by- Figures 4 and 5, the die structure is formed of halves 2| accurately aligned and held together by dowels 22 and bolts extended through bolt holes 23 and the interior of the structure is shaped like that of the structure in Figures 1, 2 and 3, the lower end of the bore l6 forming the molding cavity I! for the article to be forged, in this case also a drill bit B, the end of the bit being shaped by the die member 20 centered by the pin I9'engaging in the hole I8.

Although the drawing illustrates the molding of a four-pointed bit, it is evident that a two, six or eight point bit can be forged with equal success and that the structure can be efficiently used for the forging of other articles. In the manufacture of six-point or greater" type bits a very decided advantage arises in that the die structure can be disassembled and the finished bit readily removed, which cannot be accomplished successfully with prior types of dies.

I have showna practical and eflicient embodiment of the various features of my invention, but I do not desire to be limited to the exact construction, arrangement and operation shown and described, as changes and modifications may readily be made without departing from the scope and spirit of the invention,

I claim as follows:

In the drop forging of drill bits, a female die element of circular cross section throughout its extent and composed of interchangeable quarter segments, bolts extending in a common plane transversely through adjacent sections at points outside of the axis of said element for securing said elements together in accurate alignment, said segments having recesses for the ends of the bolts for keeping said ends within the circumferential surface of said element, and a plunger for entering the die cavity for forging aningot of metal placed therein to form the desired article.

MARTIN BENJAMIN WOLF. 

